Golf club

ABSTRACT

Provided is a golf club which allows for hitting a golf ball long distance and enhancing the durability of the golf club. The golf club has: a body portion welded and integrally attached with a face portion made of a rolled material. A back surface of the face portion has at least one groove provided at a location lower than a center of gravity on a striking face of the face portion. The at least one groove is extending from a proximity of a toe portion to a proximity of a heel portion. Moreover, three grooves can be provided evenly spaced apart along a direction intersecting with a direction heading from the toe portion to the heel portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Japanese Patent Application No. 2019-183578, filed on Oct. 4, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

This present disclosure relates to a metal golf club, and more particularly, to a golf club which allows for hitting a golf ball long distance and enhancing the durability of the golf club.

BACKGROUND ART

A performance required for a golf club has been generally like that, a long distance that a golf ball can fly is for a wood type golf club which represents a driver, while a desired target point a golf ball can reach is for an iron type golf club. The iron type golf club (hereinafter referred to as “the iron”), however, has been recently required for a long distance that a golf ball can fly, as well as the wood type golf club. A golf club disclosed in the undermentioned Patent Document 1 has grooves curved at the same direction at least either of the crown portion or the sole portion, thus allowing for an increased coefficient of restitution of the golf club head, thereby permitting a golf ball to fly a longer distance. On the other hand, a golf club disclosed in the undermentioned Patent Document 2 has the thickness of the face portion to be thin and the ribs formed extending to the back surface of the face portion from the rear portion of the golf club head, whereby to prevent the launch velocity of a golf ball from varying over the total part of the face portion of the golf club.

For the iron as well as a wood type golf club, the increased coefficient of restitution (COR) is also thought to be an effective means for hitting a golf ball long distance. To increase the coefficient of restitution (COR) of a golf club, it is necessary to make a face portion of the golf club to easily flex or deflect upon impact with a golf ball during golf swing. To make the face portion to easily flex or deflect upon impact with a golf ball during golf swing, there are known three approaches such as: (1) to make the thickness of the face portion club to be thinner, (2) to make the young's modulus of the face portion to be smaller, and (3) to make the area of the face portion to be larger. Among the above-mentioned three approaches, the second approach is difficult because the young's modulus is the characteristic value of the material and an iron-based material is mainly used as the material of the iron. The third approach is not preferred because the iron to hit a golf ball on the ground possibly has the center of gravity to be shifted more upward on the face portion. Therefore, the first approach is preferred the most. The first approach to make the thickness of the face portion to be thinner, however, has another problem to deteriorate durability of the face portion of the golf club. Therefore, the conventional iron has not satisfied both of increasing the coefficient of restitution of the golf club head to hit the golf ball longer distance and enhancing the durability of the face portion of the golf club head.

Patent Document 1: JP 2018-143523A

Patent Document 2: JP 3220762 (Utility)

SUMMARY OF THE INVENTION

The present disclosure has been achieved to solve the problems of the prior art as mentioned above. The present disclosure provides a golf club which allows for hitting a golf ball long distance and enhancing the durability of the golf club.

The present disclosure provides a golf club which has a body welded integrally with a face portion made of high-strength material to enhance the durability of the face portion.

The present disclosure provides a golf club which has a back surface of a face portion formed with grooves extending from a proximity of a toe portion to a proximity of a heel portion, thus causing the face portion to easily flex or deflect and to thereby increase the coefficient of restitution of the face portion.

The present disclosure provides a golf club which has a back surface of a face portion stamped to form grooves, to thereby enhance the durability of the face portion.

In order to solve the above-mentioned problems, according to a first embodiment of the present disclosure, a golf club is a metal golf club, and the golf club includes: a body portion, having: a sole portion at a bottom section to be put on a ground, a topline portion at an upper section, a toe portion at a front section, a heel portion at a rear section, and a hosel portion configured to attach the body portion to a shaft; and a face portion, being welded with the body portion and having a striking face for hitting a golf ball. A back surface of the face portion has at least one groove, being provided at a location lower than a center of gravity on the striking face of the face portion and extending from a proximity of the toe portion to a proximity of the heel portion.

A golf club according to a second embodiment of the present disclosure is within the first embodiment of the present disclosure, in which the at least one groove includes plural grooves, and the plural grooves are provided parallel to each other along a direction intersecting with a direction heading from the toe portion to the heel portion.

A golf club according to a third embodiment of the present disclosure is within the second embodiment of the present disclosure, in which the plural grooves are provided evenly spaced apart along the direction intersecting with the direction extending from the toe portion to the heel portion.

A golf club according to a fourth embodiment of the present disclosure is within the third embodiment of the present disclosure, in which the plural grooves are provided through a stamping operation.

A golf club according to a fifth embodiment of the present disclosure is within the fourth embodiment of the present disclosure, in which the face portion is made of a rolled material rolled along a direction heading from the topline portion to the sole portion in a rolling operation.

A golf club according to a sixth embodiment of the present disclosure is within the fifth embodiment of the present disclosure, in which the body portion is made of a low-carbon forged steel.

A golf club according to a seventh embodiment of the present disclosure is within the sixth embodiment of the present disclosure, in which each of the grooves has 0.4 mm in depth and a semi-arc shape in cross-section, and the face portion has a thickness to be less than or equal to 2.1 mm.

A golf club according to the present disclosure includes: a back surface of a face portion, having at least one groove which is provided at a location lower than a center of gravity on a striking face of the face portion and are extending from a proximity of a toe portion to a proximity of a heel portion, whereby causing the face portion to easily flex or deflect and to thereby increase the coefficient of restitution, which results in allowing for hitting a golf ball long distance.

A golf club according to the present disclosure also allows for enhancing the durability of the golf club head, because the grooves are provided through a stamping operation.

BRIEF DESCRIPTIONS OF DRAWINGS

FIGS. 1A and 1B are overall views to show a golf club in accordance with a first embodiment of the present disclosure. FIG. 1B is a front view of the golf club. FIG. 1A is a left side view of FIG. 1B.

FIG. 2 is a cross-sectional view taken along section lines A-A in FIG. 1B.

FIG. 3 is a cross-sectional view taken along section lines B-B in FIG. 2.

FIGS. 4A and 4B are elevated cross-sectional views in P portion of FIG. 2. FIG. 4A is an elevated cross-sectional view to show a first embodiment of the present disclosure, wherein three grooves are formed through stamping operation. FIG. 4B is an elevated cross-sectional view to show a modified example in accordance with a first embodiment of the present disclosure, wherein three grooves are formed through cutting operation.

FIG. 5 is an illustration to show a golf club in accordance with a second embodiment of the present disclosure, corresponding to FIG. 3.

FIGS. 6A and 6B are elevated cross-sectional views. FIG. 6A is an illustration to show a golf club in accordance with a second embodiment of the present disclosure, corresponding to FIG. 4A. FIG. 6B shows a face portion of a conventional golf club without any grooves, corresponding to FIG. 4B.

FIG. 7 is a comparative table to show a result of durability test with regarding to golf clubs according to embodiments of the present disclosure, compared with a conventional golf club.

DETAILED DESCRIPTION

Embodiments according to the present disclosure are hereinafter described in detail with reference to accompanying drawings.

FIGS. 1A and 1B are overall views to show a golf club 1 in accordance with a first embodiment of the present disclosure. FIG. 1B is a front view of the golf club 1. FIG. 1A is a left side view of FIG. 1B. FIG. 2 is a cross-sectional view taken along section lines A-A in FIG. 1B. FIG. 3 is a cross-sectional view taken along section lines B-B in FIG. 2. FIGS. 4A and 4B are elevated cross-sectional views in P portion of FIG. 2. FIG. 4A is an elevated cross-sectional view to show a first embodiment of the present disclosure, wherein three grooves are formed through stamping operation. FIG. 4B is an elevated cross-sectional view to show a modified example in accordance with a first embodiment of the present disclosure, wherein three grooves are formed through cutting operation.

Note that, a golf club 1 shown in FIGS. 1A to 4B is an iron type golf club.

The gold club 1 includes: a face portion 12, being disposed at a front face of the gold club 1 and having a striking face for hitting a golf ball; a hosel portion 13, being a shaft connection portion on a shaft side, and configured to attach a shaft 18; a topline portion 14, being disposed at an upper section; a toe portion 15, being disposed at a front section; a sole portion 16, being disposed at a bottom section to be put on a ground; and a heel portion 17, being disposed at a rear section. And, the shaft 18 is inserted and connected to the hosel portion 13 of the gold club 1.

A body portion, including the hosel portion 13, the topline portion 14, the toe portion 15, the sole portion 16 and the heel portion 17, is formed through hot forging a low-carbon steel, such as “S20C” or the like. The face portion 12 made of a rolled material is welded with the body portion to be integrally fixed therewith (refer to FIG. 2).

The material of the face portion 12 is a special steel where a vanadium is added to the material “SAE8655”, regarding the detailed components and contents, including: carbon (C) 0.40-0.80 wt %, silicon (Si) less than or equal to 0.60 wt %, manganese (Mn) 0.60-1.50 wt %, phosphorus (P) less than or equal to 0.020 wt %, sulfur (S) less than or equal to 0.025 wt %, chrome (Cr) 0.30-1.00 wt %, nickel (Ni) 0.30-0.80 wt %, molybdenum (Mo) 0.10-0.50 wt %, vanadium (V) 0.05-0.40 wt %, and the rest iron (Fe) and inevitable impurities (refer to Japanese Patent No. 4280565).

The face portion 12 is rolled along a direction heading from the topline portion 14 to the sole portion 16 as denoted an arrow 19 (i.e., a rolling direction) in FIG. 1B, in a rolling operation. A thickness of the face portion 12 is 2.06 mm. When a direction heading from the toe portion 15 to the heel portion 17 (hereinafter referred to as “toe-heel direction”) is a longitudinal direction, eleven score lines 122 are formed on a striking face 121 of the face portion 12, and these eleven score lines 122 are evenly spaced apart and parallel to each other along a direction intersecting with the toe-heel direction.

A back surface 123 of the face portion 12 has at least one groove 125 provided at a location lower than a center of gravity 124 (equal to a foot of a perpendicular taken from a center of gravity of a golf club head to the striking face 121) on the striking face 121 of the face portion 12. The groove 125 is provided extending from a proximity of the toe portion 15 to a proximity of the heel portion 17. As shown in FIG. 3, three grooves 125 are provided evenly spaced apart and parallel to each other along the direction intersecting with the toe-heel direction. The groove 125 has an arc-like groove 125A located at a proximity of the toe portion 15 and formed extending upwardly along an arc of the toe portion 15. This arc-like groove 125A causes a size of so-called “sweet spot” to be expanded toward the toe portion 15. FIG. 4A is an elevated cross-sectional view to show a first embodiment of the present disclosure, wherein three grooves 125 are formed through stamping operation. These three grooves 125 are formed through stamping operation by a punch 21. The groove 125 is formed in semi-arc-like shape in cross-section, and the groove 125 has 0.4 mm in depth and 0.5 mm in radius R. Two convex surfaces 127, 127 located between two grooves 125, 125 are formed slightly lower than the back surface 123, so that the groove 125 has a shape that is easily for performing stamping operation. FIG. 4B is an elevated cross-sectional view to show a modified example in accordance with a first embodiment of the present disclosure, wherein the groove 125 is formed through cutting operation by an end mill 22. The groove 125 is formed in semi-arc-like shape in cross-section, and the groove 125 has 0.4 mm in depth and 0.5 mm in radius R, as well as shown in FIG. 4A.

FIGS. 5 and 6A show a golf club in accordance with a second embodiment of the present disclosure, wherein one groove 126 is formed through cutting operation by the end mill 22 and is located lower than the center of gravity 124 on the striking face 121 of the face portion 12. The groove 126 is formed extending from a proximity of the toe portion 15 to a proximity of the heel portion 17. The groove 126 has an arc-like groove 126A located at a proximity of the toe portion 15 and formed extending upwardly (more upwardly than as in FIG. 3) along an arc of the toe portion 15. This arc-like groove 126A causes a size of so-called “sweet spot” to be expanded toward the toe portion 15. As shown in FIG. 6A, the groove 126 is formed as a wide groove having 3.0 mm in width and 0.2 mm in depth and 0.5 mm in radius R at both ends in cross-section. For comparison, FIG. 6B shows a conventional face portion 12 without any grooves, corresponding to FIG. 4B.

FIG. 7 is a comparative table to show a result of durability test with regarding to golf clubs according to embodiments of the present disclosure, compared with a conventional golf club. As shown in “columns of FIG. 4A, FIG. 4B and FIG. 6A” of FIG. 7, the grooves 125 or 126 formed in the back surface 123 of face portion 12 contribute to a higher coefficient of restitution (0.828) in comparison to a coefficient of restitution (0.826) of a conventional golf club without any grooves, thus allowing for an increased amount of deflection (1.2% to 2.1% up) of the face portion 12 upon impact with a golf ball during golf swing, thereby permitting a golf ball to fly a longer distance.

In addition, the grooves 125 or 126 are formed along a direction perpendicular to a rolling direction 19 of the face portionl2, thus causing it hard to produce a crack. Specially, the grooves 125 formed through stamping operation according to a first embodiment of the present disclosure shown in FIG. 4A, will not cut a metal structure extending along the rolling direction 19 of the face portion 12. As shown in the result of durability test at the head velocity of 40 m/s in FIG. 7, the grooves 125 or 126 formed through stamping operation, therefore, allows for enhancing the durability of the face portion 12 in comparison to another embodiment of the present disclosure shown in FIGS. 4B and 6A, wherein the grooves 125 or 126 are formed through cutting operation.

Various embodiments of the present disclosure have been described with reference to the accompanying drawings, however the above-mentioned description and drawings are not to be construed as limiting the disclosure. For example, the number of pieces of the grooves 125 may be more than one, and is not to limit to three as in the above-mentioned embodiment shown in FIGS. 4A and 4B. For another example, the cross-sectional shape of the groove 125 may be other shape such as trapezoid or the like, and is not to limit to a semi-arc as in the above-mentioned embodiment shown in FIGS. 4A and 4B. For another example, the above-mentioned embodiments of the present disclosure can be applied to not only the irons but also pitching wedges as well as approach wedges. For another example, the thickness of the face portion 12 is preferably 2.06 mm, and may be less than or equal to 2.1 mm.

REFERENCE SIGNS LIST

1 golf club

12 face portion

121 striking face

122 score line

123 back surface

124 center of gravity

125 groove

125A arc-like groove

126 groove

126A arc-like groove

127 convex surface

13 hosel portion

14 topline portion

15 toe portion

16 sole portion

17 heel portion

18 shaft

19 rolling direction of face portion

21 punch

22 end mill 

1. An iron type golf club, comprising: a body portion, having: a sole portion at a bottom section to be put on a ground, a topline portion at an upper section, a toe portion at a front section, a heel portion at a rear section, and a hosel portion configured to attach the body portion to a shaft; and a face portion, being welded with the body portion and having a striking face for hitting a golf ball, wherein a back surface of the face portion has a plurality of grooves being provided at a location lower than a center of gravity on the striking face of the face portion to extend in lines parallel to each other and evenly spaced apart from a proximity of the toe portion to a proximity of the heel portion. 2-3. (canceled)
 4. The iron type golf club according to claim 1, wherein the plural grooves are provided through a stamping operation.
 5. The iron type golf club according to claim 4, wherein the face portion is made of a rolled material rolled along a direction heading from the topline portion to the sole portion in a rolling operation.
 6. The iron type golf club according to claim 5, wherein the body portion is made of a low-carbon forged steel.
 7. The iron type golf club according to claim 6, wherein each of the plural grooves has 0.4 mm in depth and a semi-arc shape in cross-section, and the face portion has a thickness to be less than or equal to 2.1 mm. 